Photoemission yield study of the fermi level position on the clean SnO₂(110) surface exposed to oxygen

Electronic properties of the space charge layer of the clean SnO₂(110) surface have been studied using photoemission yield spectroscopy (PYS) associated with Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) control. Special attention has been paid to determination of the influence of ion bombardment cleaning as well as oxygen chemisorption. Depending on the annealing temperature and oxygen exposure, the variation of the Fermi level position was observed and analyzed together with the changes in the effective density of the filled electronic states localized in the band gap below the Fermi level E_F and in the upper part of the valence band. Two types of electronic state bands were observed and attributed to the different types of surface structural defects.